Conventionally, a communication from a server to a storage device (hereinafter referred to as a “storage communication”) demanded a higher communication performance than that of a communication between servers (hereinafter referred to as an “inter-server communication”). Therefore, separate networks were organized (FIG. 1). Here, an inter-server communication network is called a Local Area Network (LAN), whereas a storage communication network is called a Storage Area Network (SAN). Moreover, a server and a Fibre Channel (FC) switch, and a storage device and an FC switch are respectively connected by an FC, so that communication paths are multiplexed to improve Reliability Availability Serviceability (RAS) (fabric multiplexing).
With the recent speed-up of Ethernet, it has become possible to implement an integrated network where an inter-server communication and a storage communication are integrated. Techniques for handling a packet of an FC, which is a standard of a SAN, with Ethernet include Fibre Channel over Ethernet (FCoE).
At the initial stage of a LAN/SAN integrated network using FCoE, a connection between an End Node (a server or a storage) and an FCoE switch was implemented as a 1-hop connection (FIG. 2). Moreover, an End Node (a server or a storage) and an FCoE switch are connected by FCoE, so that communication paths are made redundant to improve RAS (redundant fabric).
Additionally, a connection between an End Node and an FCoE switch is implemented as a multi-hop connection in the current LAN/SAN integrated network (FIG. 3).
Ethernet is described next.
A network topology of Ethernet conventionally had a tree structure.
Currently, the network topology of Ethernet has been expanded to a topology having a plurality of path options as illustrated in FIGS. 4 and 5. In such topologies, techniques such as Multi-chassis Link Aggregation (MLAG), Transparent Interconnection of Lots of Links (TRILL), and Shortest Path Bridging (SPB), and the like are used.
With the FCoE multi-hop connection, a network is shared although links of end nodes are made redundant (FIG. 6). Accordingly, this poses a problem in that influence is exerted on a plurality of storage network systems when a fault occurs.
Furthermore, documents such as Japanese Laid-open Patent Publication No. 2013-85166, Japanese Laid-open Patent Publication No. 2012-227651, and the like are well-known.